Perform build and magnum tuning

Building o//third_party/python now takes 5 seconds on my PC

This change works towards modifying Python to use runtime dispatching
when appropriate. For example, when loading the magnums in the socket
module, it's a good idea to check if the magnum is zero, because that
means the local system platform doesn't support it.

third_party/python/Modules/clinic/spwdmodule.inc

@@ -0,0 +1,70 @@
+/* clang-format off */
+/*[clinic input]
+preserve
+[clinic start generated code]*/
+
+#if defined(HAVE_GETSPNAM)
+
+PyDoc_STRVAR(spwd_getspnam__doc__,
+"getspnam($module, arg, /)\n"
+"--\n"
+"\n"
+"Return the shadow password database entry for the given user name.\n"
+"\n"
+"See `help(spwd)` for more on shadow password database entries.");
+
+#define SPWD_GETSPNAM_METHODDEF    \
+    {"getspnam", (PyCFunction)spwd_getspnam, METH_O, spwd_getspnam__doc__},
+
+static PyObject *
+spwd_getspnam_impl(PyObject *module, PyObject *arg);
+
+static PyObject *
+spwd_getspnam(PyObject *module, PyObject *arg_)
+{
+    PyObject *return_value = NULL;
+    PyObject *arg;
+
+    if (!PyArg_Parse(arg_, "U:getspnam", &arg)) {
+        goto exit;
+    }
+    return_value = spwd_getspnam_impl(module, arg);
+
+exit:
+    return return_value;
+}
+
+#endif /* defined(HAVE_GETSPNAM) */
+
+#if defined(HAVE_GETSPENT)
+
+PyDoc_STRVAR(spwd_getspall__doc__,
+"getspall($module, /)\n"
+"--\n"
+"\n"
+"Return a list of all available shadow password database entries, in arbitrary order.\n"
+"\n"
+"See `help(spwd)` for more on shadow password database entries.");
+
+#define SPWD_GETSPALL_METHODDEF    \
+    {"getspall", (PyCFunction)spwd_getspall, METH_NOARGS, spwd_getspall__doc__},
+
+static PyObject *
+spwd_getspall_impl(PyObject *module);
+
+static PyObject *
+spwd_getspall(PyObject *module, PyObject *Py_UNUSED(ignored))
+{
+    return spwd_getspall_impl(module);
+}
+
+#endif /* defined(HAVE_GETSPENT) */
+
+#ifndef SPWD_GETSPNAM_METHODDEF
+    #define SPWD_GETSPNAM_METHODDEF
+#endif /* !defined(SPWD_GETSPNAM_METHODDEF) */
+
+#ifndef SPWD_GETSPALL_METHODDEF
+    #define SPWD_GETSPALL_METHODDEF
+#endif /* !defined(SPWD_GETSPALL_METHODDEF) */
+/*[clinic end generated code: output=07cd8af0afd77fe7 input=a9049054013a1b77]*/